Publishing / Year of Carbon

How can geoscience deliver opportunities for decarbonisation? – Author Q & A with Prof Mike Stephenson

Krafla geothermal plant in Iceland. Source – Ásgeir Eggertsson, Wikimedia Commons

In January 2019, Mike Stephenson (BGS), Dave Schofield (BGS), Sebastian Gieger (Heriot-Watt University) and Phil Ringrose (Equinor/NTNU) convened the Geological Society’s Bryan Lovell meeting on The role of geological science in the decarbonisation of power production, heat, transport and industry.

The meeting explored themes ranging from energy storage, hydroelectric power, geothermal energy, the hydrogen economy, carbon capture and storage (CCS) and minerals for the energy transition. Today, Mike Stephenson and colleagues have published a review paper in Petroleum Geoscience setting out the current status and future directions of geoscience and its role in decarbonisation based on the discussions during the meeting. As well as looking at policy needs, the review gives clues about what activities the next generation of geoscientists and energy engineers might need to engage in; meeting the decarbonisation challenge will require both new and established geological skills.

You can find the paper in Petroleum Geoscience on the Lyell Collection, where it is free to access.

We caught up with one of the authors Professor Mike Stephenson, Executive Chief Scientist for Decarbonisation and Resource Management at the British Geological Survey for a chat about the links between geoscience and decarbonisation.

What are some of the key ways the geosciences can contribute to decarbonisation?

Heat flow map of the UK. Source: British Geologicla Survey.

The most obvious way is geothermal. About 20% of the UK’s emissions come from natural gas-fired heating of buildings, mainly homes. Decarbonising these heating systems is a challenge. You could perhaps convert to electricity but this would hugely increase demand, you could convert natural gas heating to hydrogen, which would be expensive – or you could use geothermal heat.  The available heat in the UK (including deeper hot dry rock and shallow geothermal), is around 200 EJ (1 EJ is 1018) joules). This is enough for about 100 years of heat supply at present consumption rates. Perhaps the most suitable for UK housing would be low-enthalpy (shallow) heat. The British Geological Survey’s (BGS) UKGEOS Glasgow project is looking right now at the possibilities for shallow heat to be extracted from old coalmines.

Other ways that geoscience can contribute to decarbonisation relate to the earth as an energy store or as a store for CO2. In compressed air energy storage (CAES), subsurface caverns can help to provide grid-scale energy storage to even out the intermittence of renewables. They can also be used to store hydrogen to cope with interseasonal variation of hydrogen use on an industrial scale. Perhaps best known for its direct way of dealing with emissions reduction is carbon capture and storage (and its relative carbon capture storage and utilisation, CCUS). At a recent meeting I heard the special advantages of CCS succinctly put as 1) the capability to achieve very high emissions reductions from power and energy-intensive industry; (2) that it can be applied to existing and future assets; and (3) that it can be scaled up for negative emissions in the event of emissions reductions not falling within the envelope of the Paris agreement.

There are also some very innovative ideas out there for energy storage, for example turning rocks directly into batteries. Can the distribution of ‘trace’ metals in mudstones, for example, be used to imitate redox flow batteries? Can we use salt caverns as reservoirs for battery electrolytes?

So I think geoscience has an enormous amount to contribute to decarbonisation. Indeed it is unlikely that decarbonisation, and ambitious aims such as the UK’s net zero-carbon commitment by 2050, can be achieved without geoscience and the subsurface.

What specific skills and experience do geoscientists bring to global efforts to tackling carbon emissions?

I think there are two areas that geoscientists bring special knowledge and expertise. One is just the sheer historic scale of our knowledge of earth systems, the carbon cycle and energy. Not many scientists consider the long term geological-scale part of the carbon cycle that leads to climate change  – the carbon interchange between the geosphere and the biosphere.

The Carbon Cycle. Source: The Geological Society educational materials.

This gives us a perspective on climate change that no other scientists have. As geoscientists, we’ve seen global warming on the grand scale numerous times in geological history: the Palaeocene-Eocene Thermal Maximum, the end of the Younger Dryas. So we understand the big cycles of change. But we also have crucial geological knowledge – an understanding of how rocks on the one hand can confine and contain fluids, as well as allow fluids to flow. In the first case, knowledge of containment is important for storage – for example of CO2 in CCS, or for CAES, or for hydrogen storage. In the second, free movement of fluids is important for geothermal, otherwise heat dries up.

You can read more about the climate change over geological time in the Geological Society’s climate change statement: ‘Climate Change: evidence from the geological record.

Geoscientists are often associated with extraction and unsustainable resources – how can we change people’s minds?

Last year I visited the famous Iron Bridge in Shropshire. One of the first structures of the industrial revolution, its construction was facilitated by the presence of local iron ore, limestone and coal. Like other developments of the industrial revolution, the presence of geological materials was vital. So it’s true that geology was part of a period that we might call ‘carbonisation’. But geological materials will also be needed for decarbonisation – rocks to store energy and CO2, and to obtain sustainable heat from the earth. Much of the knowledge that we’ve gained over decades in the oil and mining industry will be useful in this new endeavour. Understanding the geothermal resource and the best way to extract heat needs the same observation, description, process understanding and modelling as extraction of oil or

Consumption of mineral raw materials has significantly increased since the industrial revolution, both in volume and variety of minerals used. 
© World Economic Forum, 2018

gas. Understanding the geomechanical and geochemical effects of hydrogen or CO2 storage will draw heavily on techniques from the hydrocarbon and mining industries. We’ll of course still need to get metals from the ground to keep the low carbon transition going – for example cobalt and lithium for batteries – but we’ll have to learn to use these as part of a circular economy that minimises waste and maximises recycling.

I think these are fascinating applications of geoscience that will continue to attract bright young minds who want to turn their geological knowledge to something useful and sustainable. And what could be more inspiring than contributing to saving the planet?

A wide range of technologies and tools which will contribute to decarbonisation were discussed at the Bryan Lovell meeting – what are some common challenges they all face?

As I said earlier, many of the challenges are the same across several geological decarbonisation technologies – how to confine and contain fluids when needed, and how to allow fluids to flow when needed. This needs a better understanding of the properties of rocks at the nano, micro and macro scale, including their primary characteristics and any later diagenetic or fracture characteristics. But we geoscientists are pretty good in these areas already. Perhaps more difficult are the challenges that are not entirely within our power to resolve – for example how legislation enables subsurface usage, and how the public views the use of the subsurface. The first  – the collective application of the law – should allow the use of the subsurface in decarbonisation within limits that protect property, investment and environmental and public safety. Geothermal is a case in point. At the moment there isn’t – in the UK at least – the legislation in place that will protect a geothermal company’s investment or stop the overuse (unsustainable use) of underground heat. Geologists need to be able to engage policy and law makers to facilitate good legislation that will turn into good regulation. But perhaps this is something geoscientists haven’t done much of in the past – so we’re uncertain about how to do it.

The ‘geoscience decarbonisation community’ need to get together more, realise our common challenges and learn to speak with a common voice so that we get noticed by the legislators and policy makers.

As has been pointed out in numerous recent conferences on geoscience in the public arena, the views of the public – the non-geological public – to new uses of the subsurface are not always favourable. Like working with policy makers and legislators, geoscientists will need to continue to develop in the area of public engagement.

What are the challenges we face if these technologies are not developed quickly enough?

While researching my recent book (Energy and Climate Change, Elsevier 2018), I was amazed by the sheer inertia that fossil fuels have. For many countries with large reserves, coal, oil and gas are just the easiest way to supply energy to rapidly growing industry and population. In India, despite a great increase in renewables, big coal power stations with potential 40-year lifetimes are still being brought online. The Economist magazine, only a few weeks ago, covered the growth of coal-fired power in Africa (Economist July 27th 2019). It may be that CCS will be the only way to decarbonise this power. CCS similarly is still one of the few ways to work with difficult-to-decarbonise parts of the modern economy, for example cement and chemicals manufacture, and steel making. Though many environmentalists and climate specialists have concerns about it, BECCS (bioenergy and CCS) is the only negative emissions technology that could work at the scale that would be needed to address an overshoot beyond the limits of the Paris agreement. The environmental limits of BECCS are still unknown but if it can be made to work, it has a strong geological element – the geological storage side.

Tyndall Centre animation on Biomass Energy Carbon Capture and Storage.

What do you think the most important next step is for the geoscience community in contributing to decarbonisation efforts?

This is simple. The ‘geoscience decarbonisation community’ need to get together more, realise our common challenges and learn to speak with a common voice so that we get noticed by the legislators and policy makers. We have a really inspiring and practical message. Let the geologists get on with helping to decarbonise!

Co-author Phil Ringrose added: This review paper, just out, suggests geoscience is critical – the solutions are ‘under our feet’. Building on conclusions reached at the 2019 Bryan Lovell meeting, the paper argues that geoscience is critical to decarbonisation and we need the geoscience community to engage and to influence decision makers.  As well as looking at policy needs, the review gives clues about what activities the next generation of geoscientists and energy engineers might engage in to meet the decarbonisation challenge which will need both new and more established skill sets. 

You can find out more about the 2019 Bryan Lovell Meeting including watching the talks and reading the policy briefing note covering the main themes of the meeting here.

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